Scientists around globe unite to combat AIDS

Effort focusing on cooperation will share technology, data, funds in search for vaccine

March 24, 2006|By Laurie Goering, Tribune foreign correspondent

JOHANNESBURG — Each day, 13,000 people worldwide contract the virus that causes AIDS, the United Nations estimates. But two decades after the disease was first identified, scientists are still struggling to find a vaccine that could help contain its spread.

More than 70 AIDS vaccines have reached human trials. Only one has made it to advanced testing, and it has shown little sign of being effective, according to the International AIDS Vaccine Initiative, an advocacy organization.

Unexpected difficulty

"Making a vaccine has turned out to be much more difficult than we ever believed," Dr. Barton Haynes, a leading vaccine researcher at Duke University, said back in 1999. Today, he and other frustrated scientists around the globe have abandoned their race to be first to create an effective vaccine and decided to try something new: cooperation.

Using a model pioneered by the Human Genome Project, AIDS researchers worldwide are joining forces and sharing labs, data, technology and funding to try to solve some of the more intractable mysteries surrounding HIV infection, with the aim of finally producing a vaccine.

With 40 million people infected with the virus and 45 million more expected to get it by 2010 without intervention, "we all feel a sense of extraordinary urgency," said Haynes, who leads one of the first two investigative centers created under the Global HIV Vaccine Enterprise, which was launched last year.

The centers, one at the U.S. National Institute of Allergy and Infectious Disease and the other at Duke University, will pull together AIDS experts from throughout the world--including India, South Africa, Thailand and China--to do what Haynes calls "desperately needed" basic research on HIV infection in clinics and laboratories in major infection zones, particularly sub-Saharan Africa.

At public clinics in South Africa, Malawi, Uganda and Tanzania, for instance, researchers will use RNA tests to try to find between 600 and 1,000 people who are in their first few days of HIV infection and who have not yet begun producing antibodies to the virus. Then they will track them in an effort to understand how the virus behaves in its first few days in the human body and how the body responds.

The data from such studies and other research information--including, potentially, the genetic sequencing of the virus--are to be put on a public Web site for use by all AIDS researchers and members of the "virtual consortium." Scientists may use the data to try to come up with new ideas for a vaccine, with the aim of getting vaccine candidates in human testing by 2009.

A need to dig deeper

Basic research should help "tackle the big questions," said Dr. Salim Abdool Karim, director of the Center for the AIDS Program of Research in South Africa, one of the members of the new consortium. But "the roadblocks are so large and fundamental it's impossible to predict when we'll overcome this hurdle," he said.

South Africa has more than 5 million people infected with the virus, one of the larger AIDS epidemics in the world. That means "South Africa and Africa have the most to gain" from a vaccine, said Carolyn Williamson, an AIDS researcher at the Institute of Infectious Disease and Molecular Medicine at the University of Cape Town.

South Africa already is involved in creating and testing potential AIDS vaccines, but its vaccine candidates, like most of those worldwide, show promise only in limiting the level of virus in the bloodstream of those who become infected.

The problem, scientists say, is that most vaccines--for diseases such as measles, for instance--help a newly infected person clear the virus or bacteria from the blood, ensuring the disease never develops. With HIV, however, there is no known case of an infected person ever clearing the virus from his or her body, which means an effective drug would have to prevent infection.

"We're trying to do something that has not been accomplished for any vaccine yet," Haynes said.

30 drugs in human trials

Nearly all the HIV vaccines currently in human trials--about 30--focus on achieving a particular kind of immune response in the bloodstream to the virus. The first results from those studies should be released next year. The new research effort, however, will also focus on some neglected areas of study, including the possibility that a nasal-spray vaccine could stimulate the body's mucus linings--including in the genitals--to neutralize HIV before it enters the bloodstream and causes infection.

The idea for that theory comes from a group of prostitutes in Africa who, despite regularly having unprotected sex with HIV-positive men, have never become positive for the virus themselves. Scientists, including Haynes, think something in the prostitutes' mucus linings may neutralize the virus, keep it from entering the bloodstream or allow them to fight off infection.

The Global HIV Vaccine Enterprise, first proposed by two dozen HIV vaccine researchers in 2003 and backed by the Bill & Melinda Gates Foundation, has the financial support of the Group of Eight developed countries, including the United States, which is investing around $500 million a year in AIDS vaccine development efforts.